ADP3307

–8–

REV. 0

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

+

C1

100 F

10V

L1

6.8 H

D1

1N5817

C2

100 F

10V

SW1

SW2

GND

FB

ADP3000-ADJ

R1

120

R2

30.1k

1%

Q1

2N3906

ADP3307-3.3

IN

OUT

GND

SD

R3

124k

1%

R4

274k

Q2

2N3906

C3

2.2 F

3.3V@100mA

Figure 24. Constant Dropout Post Regulator

6-Lead Plastic Surface Mount

(RT-6)

0.122 (3.10)

0.106 (2.70)

PIN 1

0.071 (1.80)

0.059 (1.50)

0.118 (3.00)

0.098 (2.50)

0.075 (1.90)

BSC

0.037 (0.95) BSC

1

3

4

5

6

2

0.009 (0.23)

0.003 (0.08)

0.022 (0.55)

0.014 (0.35)

10

°

0

°

0.020 (0.50)

0.010 (0.25)

0.059 (0.15)

0.000 (0.00)

0.051 (1.30)

0.035 (0.90)

SEATING

PLANE

0.057 (1.45)

0.035 (0.90)

Constant Dropout Post Regulator

The circuit in Figure 24 provides high precision with low drop-

out for any regulated output voltage. It significantly reduces the

ripple from a switching regulator while providing a constant

dropout voltage, which limits the power dissipation of the LDO

to 30 mW. The ADP3000 used in this circuit is a switching

regulator in the step-up configuration.